White light is obtained by combining a blue LED (light emitting diode) that emits blue light and a fluorescent substance of yellow, red, or the like, for example. Such white LEDs are used for illumination, and energy saving effect is expected.
A nitride semiconductor is used for the blue LED, and a quantum well structure of InGaN/GaN, for example, is used for the light emitting layer. Since the lattice constant of InGaN is different from the lattice constant of GaN, the quality of the InGaN crystal layer may be degraded and the light emission efficiency may be reduced, depending on the fabrication conditions of the quantum well structure of InGaN/GaN. It is desired to provide a semiconductor light emitting element with a high light emission efficiency.